Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual foram os ganhos de investimento em um ano em que a receita total foi de $21,779,618?
 ###Tabelas: CREATE TABLE district_122_gross_revenue_by_sources (district_122_gross_revenue_by_sources_id AUTO_INCREMENT PRIMARY KEY, Year INT, Property Taxes VARCHAR, Investment Earnings VARCHAR, Other Local Sources VARCHAR, State & Federal VARCHAR, Total Revenue VARCHAR) CREATE TABLE apertura_2002_standings (apertura_2002_standings_id AUTO_INCREMENT PRIMARY KEY, Place INT, Team VARCHAR, Played INT, Draw INT, Lost INT, Goals Scored INT, Goals Conceded INT, Points INT) CREATE TABLE cantonal_school_systems (cantonal_school_systems_id AUTO_INCREMENT PRIMARY KEY, Canton VARCHAR, Years of Kindergarten INT, Years of Kindergarten provided VARCHAR, Years of Kindergarten legally required VARCHAR, Length of Primary School INT, Length of mandatory Secondary School INT, Separate Secondary Schools? VARCHAR, Cooperative Secondary Schools? VARCHAR, Integrated Secondary Schools? VARCHAR) CREATE TABLE overtime_rules (overtime_rules_id AUTO_INCREMENT PRIMARY KEY, Length of game VARCHAR, Date VARCHAR, Away team VARCHAR, Score VARCHAR, Home team VARCHAR) CREATE TABLE solo_songs (solo_songs_id AUTO_INCREMENT PRIMARY KEY, Title VARCHAR, Russian VARCHAR, Transliteration VARCHAR, Original Text VARCHAR, Start INT)  
SELECT Investment Earnings FROM district_122_gross_revenue_by_sources WHERE Total Revenue = 21,779,618